External K+ Affects the Internal Acidification Caused by the Addition of Glucose to Yeast Cells

Valle, Eulalia; Bergillos, Lourdes; Ramos, Sofı́a

doi:10.1099/00221287-133-3-535

Cited by 4 publications

(7 citation statements)

References 11 publications

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“…In this case, the acidification was transient, as expected, due to the presence of K+ in the culture medium (Valle et al, 1987). Interestingly, pHin was 7.1 even though the pH of the medium was 3.1.…”

Section: Discussionsupporting

confidence: 66%

“…However, an exchange of H+ for K+ also seems to be involved. This system has been characterized in Neurospora crassa (Blaat & Slayman, 1987) and observed in Saccharomyces cerevisiae (Valle et al, 1987). This alkalinization is preceded by an acidification (den Hollander et al, 1981 ;Nicolay et al, 1982;Caspani et al, 1985;Valle et al, 1986;Thevelein et al, 1987b) which, in the presence of external K+, is transient but in its absence lasts for at least 10 min (Valle et al, 1987).…”

Section: S Ramos a N D Othersmentioning

confidence: 99%

“…This system has been characterized in Neurospora crassa (Blaat & Slayman, 1987) and observed in Saccharomyces cerevisiae (Valle et al, 1987). This alkalinization is preceded by an acidification (den Hollander et al, 1981 ;Nicolay et al, 1982;Caspani et al, 1985;Valle et al, 1986;Thevelein et al, 1987b) which, in the presence of external K+, is transient but in its absence lasts for at least 10 min (Valle et al, 1987). The cause of the decrease of pHi, induced by glucose is not fully understood, but may be due to the accumulation of either C 0 2 (den Hollander et al, 1981), glucose 6-phosphate (Valle et al, 1987;Eraso et al, 1987) or other organic acids, since one of the known effects of glucose is the production and secretion of these substances (Duro & Serrano, 1981;Wurst et al, 1981).…”

Section: S Ramos a N D Othersmentioning

confidence: 99%

“…However, it has been shown that in the presence of external K+ the acidification induced by glucose is transient and is followed by an alkalinization (Valle et al, 1987). If the acidification caused by glucose has any signalling function it should also occur in cells suspended in culture medium.…”

Section: Efect Of Glucose Addition To Cells Suspended In Growth Mediummentioning

confidence: 99%

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The Mechanism of Intracellular Acidification Induced by Glucose in Saccharomyces cerevisiae

Ramos¹,

Balbı́n²,

Raposo³

et al. 1989

Microbiology

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Addition of glucose or fructose to cells of Saccharomyces cerevisiae adapted to grow in the absence of glucose induced an acidification of the intracellular medium. This acidification appeared to be due to the phosphorylation of the sugar since : (i) glucose analogues which are not efficiently phosphorylated did not induce internal acidification; (ii) glucose addition did not cause internal acidification in a mutant deficient in all the three sugar-phosphorylating enzymes; (iii) fructose did not affect the intracellular pH in a double mutant having only glucokinase activity; (iv) glucose was as effective as fructose in inducing the internal pH drop in a mutant deficient in phosphoglucose isomerase activity; and (v) in strains deficient in two of the three sugar-phosphorylating activities, there was a good correlation between the specific glucose-or fructose-phosphorylating activity of cell extracts and the sugar-induced internal acidification. In addition, in whole cells any of the three yeast sugar kinases were capable of mediating the internal acidification described. Glucose-induced internal acidification was observed even when yeast cells were suspended in growth medium and in cells suspended in buffer containing K+, which supports the possible signalling function of the glucose-induced internal acidification. Evaluation of internal pH by following fluorescence changes of fluorescein-loaded cells indicated that the change in intracellular pH occurred immediately after addition of sugar. The apparent K , for glucose in this process was 2 mM. Changes in both the internal and external pH were determined and it was found that the internal acidification induced by glucose was followed by a partial alkalinization coincident with the initiation of H+ efflux. This reversal of acidification could be due to the activity of the H+-ATPase, since it was inhibited by diethylstilboestrol. Coincidence between internal alkalinization and the H+ efflux was also observed after addition of ethanol.

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Section: Discussionsupporting

confidence: 66%

Section: S Ramos a N D Othersmentioning

confidence: 99%

Section: S Ramos a N D Othersmentioning

confidence: 99%

Section: Efect Of Glucose Addition To Cells Suspended In Growth Mediummentioning

confidence: 99%

See 2 more Smart Citations

The Mechanism of Intracellular Acidification Induced by Glucose in Saccharomyces cerevisiae

Ramos¹,

Balbı́n²,

Raposo³

et al. 1989

Microbiology

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“…The signal transduction pathway requires the function of the CDC25 gene-product and one of the GTP binding proteins of the RAS family, which mediates the increase in adenylate cyclase activity (Field et al, 1987;Daniel et al, 1987;Toda et al, 1985;Broek et al, 1987;Mbonyi et al, 1988). The rapid decrease in intracellular pH which followed the addition of glucose was thought previously to mediate the cAMP increase (Caspani et al, 1985;Purwin et al, 1986;Valle et al, 1986Valle et al, , 1987, but at present, it is uncertain to what extent this acidification is the sole cause for the rise in cAMP (Eraso et al, 1987;Thevelein et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Transient increase in Ca2+ influx in Saccharomyces cerevisiae in response to glucose: effects of intracellular acidification and cAMP levels

Eilam

Othman

Halachmi

1990

Journal of General Microbiology

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Influx of 45Ca2+ into Sacckomyces cerevisiae was measured under experimental conditions which enabled measurements of initial rate of transport across the plasma membrane, without interference by the vacuolar Ca2+ transport system. Addition of glucose or glycerol to the cells, after pre-incubation in glucose-free medium for 5 rnin, caused a rapid, transient increase in 45Ca2+ influx, reaching a peak at 3-5 min after addition of substrate. Ethanol, or glycerol added with antimycin A, had no effect on 45Ca2+ infiux. We have shown previously that this increase is not mediated by an effect of the substrates on intracellular ATP levels. Changes in membrane potential accounted for only a part of the glucose-stimulated 45Ca2+ influx. The roles of intracellular acidification and changes in cellular cAMP in mediating the effects of glucose on 45Ca2+ influx were examined. After a short preincubation in glucose-free medium addition of glucose caused a decrease in the intracellular pH, [pHli, which reached a minimum value after 3 min. A transient increase in the cellular cAMP level was also observed. Addition of glycerol also caused intracellular acidification, but ethanol or glycerol added with antimycin A had no effect on [pHli. Artificial intracellular acidification induced by exposure to isobutyric acid or to CCCP caused a transient rise in Ca2+ influx but the extent of the increase was smaller than that caused by glucose, and the time-course was Merent. We conclude that intracellular acidification may be responsible for part of the glucose stimulation of Ca2+ influx. The role of the increase in cAMP level on Ca2+ influx was examined by measuring the effect of glucose and of artificial intracellular acidification on Ca2+ influx in a cyrl strain which lacks adenylate cyclase activity. In this strain, addition of glucose or isobutyric acid still led to a transient increase in Ca2+ transport. Therefore, we concluded that at least part of the increase in Ca2+ influx in response to glucose is CAMP-independent.

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Regulation of oxidoreductive yeast metabolism by extracellular factors

Fraleigh

Bungay

Fiechter³

1989

Journal of Biotechnology

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External K+ Affects the Internal Acidification Caused by the Addition of Glucose to Yeast Cells

Cited by 4 publications

References 11 publications

The Mechanism of Intracellular Acidification Induced by Glucose in Saccharomyces cerevisiae

The Mechanism of Intracellular Acidification Induced by Glucose in Saccharomyces cerevisiae

Transient increase in Ca2+ influx in Saccharomyces cerevisiae in response to glucose: effects of intracellular acidification and cAMP levels

Regulation of oxidoreductive yeast metabolism by extracellular factors

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